The invention relates to an apparatus for filling a screw bearingly supported within a housing, in particular of an extruder, for processing of pre-comminuted synthetic plastic material, wherein the filling opening of a screw housing is in flow connection with the lower outflow opening of an upright vacuum-tight receptacle for material to be processed, and wherein, within the receptacle, tools are provided which are driven by a drive means for rotation around an, in particular vertical, axis, which tools act onto the material that is introduced into the receptacle from above through a sluice. Further, the invention relates to a process for operation of such an apparatus.
An apparatus of the initially described kind is known to the applicants from practice as a vacuum hopper for injection molding or extrusion machines. Such a construction, however, cannot suitably be used for all kinds of synthetic plastic material, in particular not for such kinds of plastics which require a longer dwell time within the receptacle, for example PET (polyethylene terephthalate), for example comminuted material deriving from bottles, bottle pre-forms, foils or plates. This material, as a rule, is not pre-crystallized and requires a certain temperature and homogenous distribution before it is introduced into the screw housing for plastification.